This invention relates to pagers. In particular, it relates to pagers with visible displays of information that is sent.
A pager is a portable device for allowing a user at a remote location to receive information from a central location. In its simplest form, a pager may simply alert a number of users to the fact that their attention is required. They are then expected to call the central location to find who has called and what the message is. Some of the many refinements of this principle include selective calling which alerts only the user of a particular pager that he is being called. Another such feature is message paging which not only alerts the user with a signal of some sort but also delivers a message to the user. Other features are possible and have been used in some pagers. In increasing the number of available features, the designer of a pager normally maintains certain objectives, including some of the following. A user should be able to forget a paper until he is paged. This means that it is preferable that the pager be silent unless its user is called. It also means that the pager should be as light as possible since part of the weight of a pager is its batteries and one objective is to limit the needed electrical energy, and hence the size of the batteries required.
A conflict in the use of pagers arises when the user of a pager is in a group of people. On the one hand, it is desirable for a pager to make an unequivocal bid for the attention of its user. This has typically meant the use of a strident alert tone to minimize the possibility that the user might overlook a call. Such an alert tone can provide an unwelcome distraction when it interrupts the affairs of a group of people and may as a result become an embarrassment to the user of the pager. Often, the only remedy available to the user of the pager is to turn off the pager and thereby run the risk of missing a call. However, when he does this, he frustrates the principal purpose of a pager which is to make known to him, whatever his location, that someone has a message for him. From the point of view of the person who tries to reach the user of a pager, a switched-off pager means that the user of the pager has become unavailable.
It is evident that a desirable feature of a pager is an unobtrusive alert to its user. Such alerts have been achieved in the past with some form of indicator to the user that a call has been made while his volume has been turned down. However, such call indicators have been able to do no more than to alert the user of the need to call the communications center to find what message is there for him. If his pager is one that not only alerts him but also delivers a message, such as a numbered call, then that message is lost to him since it is not normally stored at the communications center.
The lack of utility of a pager that results when the user turns it off and receives a call is compounded further when the user receives a plurality of calls when he has turned off his sound. The user who hears a plurality of alert tones without receiving the associated messages has lost much of the utility of his pager. To make his pager the useful instrument that it should be while allowing him to continue to be an acceptable member of a social group, he needs some way to store messages that come to him while he is in a group and to recover those messages at a time when he can make use of the information.
If the user were at a fixed location, the solution would be simple. It is the conventional telephone answering service; record the message on a tape recorder for later playback. This is not a satisfactory solution, however, for the user of a pager because of the size and weight associated with a tape recorder and its associated playback equipment and the cost of such equipment. A pager that combined a tape recorder and means for playing back a recorded tape would cost too much and would be too big to be convenient for carrying as a pager.
There are several other features that are desirable to increase the utility of a pager. One of these is a priority system that allows certain callers to reach the user of the pager in spite of his attempts to turn off the volume. A priority feature could be combined with tone-only paging, with voice paging or with a data page. A tone-only, page in the absence of a display, merely alerts the user of a page to the fact that he has been paged without telling him of the source. It would be useful, in addition, to be able to inform him of the source of a tone-only page. Furthermore, if the user of a page has chosen to silence the alerts during a period of when he receives a non-priority voice page, it would be useful to him to know that he has received a voice page during the period of silence.